Centrifugal fan



Sept. 24,` 1.935. E. wlTzEl. y

CENTRIFUGAL FAN Filed Oct. 13, 1954 Fig fm. Mm ST @a uJ ou Patented Sept. 24, 1935 PATENT OFFICE y CENTRIFUGAL FAN Ernst Witzel, Racine, Wis., assigner to Young Radiator Company, Racine, Wis.

Application October 13, 1934, Serial No. 748,177

3 Claims.

My invention relates to improvements in blower fans of the centrifugal type, commonly used for moving air in heating, cooling and air conditioning equipments. f

The object of my invention is to provide a removable cut-out in the outlet throat of the fan, to improve the efficiency of the device and provide means, whereby the rotor may be easily removed through. the air outlet of the housing, thus making it possible to weld or otherwise permanently assemble the various members of the houslng.

In conventional fans of the present type, the air outlet or throat adjacent the rotor is, for obvious reasons, less in depth than the diameter of the rotor. The air duct leading therefrom, however, frequently has a greater depth than the rotor diameter. Applicant provides a throat or outlet with a depth slightly greater than the diameter of the rotor. AApplicants cut-out, when removably positioned in the throat, therefore provides convenient means for removing the rotor.

The peripheral speed of a centrifugal fan rotor, is generally very high; therefore in order to secure the greatest eiciency, a suitably curved wedge shaped cut-out is necessary. Applicants cut-out, at the point where it divides the air, is narrow, and from this point the cut-out is gradually wider or wedge shaped, comprising an inner surf-ace that curves at first rapidly away from the rotor, the lower edge registering with the housing, which continues to curve at an ever increased radius and greater distance from the rotor. Y

The outer surface of the cut-out extends downward and outward to thereby ease the adjacent air current from the outlet into the air duct without undue friction. The air is thus suitably divided and permitted to continue its outward movement, but is diverted gradually in the direction it should travel, in a manner which will hereinafter appear and as indicated in the accompanying drawing in which:

Figure 1 is a side elevation of a conventional cage type centrifugalfan, having applicants improved cut-out suitably positioned therein, a portion of the housing and a short section of the outer rotor ring being removed, to thus clearly illustrate the relative position of the essential parts.

Figure 2 is of Figure 1.

Figure 3 is an enlarged side elevation of applic-ants cut-out, as viewed from the rotor.

a sectional view taken on line 2 2,

Figure 4 is an enlarged end View of the device as shown in Figure 1.V

Figure 5 is a bottom view of applicants cutout as shown in Figure 1.

As thus illustrated the reference character A 5 is used to designate the fan housing in its entrety. This housing is preferably made from sheet steel comprising side members IU-ID and a cover Il, the edges of which are preferably folded as at l2-I2 so as to provide a surface suit- 10 able for spot welding, riveting or otherwise securely and permanently fastening these members together. I provide the usual air inlets lil- UL having inturned edges as at l5.

The cover Ii is provided with suitably posi- 15 tioned extensions I3-I3, the side members l0 being extended similarly, to thereby form a suitable air outlet, the lower surface of which is preferably on a radius with the'center of the rotor, which is design-ated in its entirety by reference 20 character B.

The rotor B comprises the usual annular blade supporting members l6|6, a central disk II having a hub I8. I provide suitably shaped, positioned, and spaced blades I9. I have thus 25 described and illustrated a conventional double cage rotor and housing therefor.

It will be understood, however, that I` have shown a conventional double cage centrifugal fan as a suitable design with which to most conveniently illustrate my improvement, which obviously may be applied to any type of centrifugal fan or to a centrifugal liquid pump.

The peripheral speed of a centrifugal fan is necessarily high and since one of the objects of 35 this invention is to provide an air outlet large enough through which the rotor may be removed, I provide a detachable cut-out which is shaped and positioned in the outlet to thereby increase the efciency of the fan and also provide the means for removing the rotor through the outlet.

Reference character C is used to designate applicants cut-out in its entirety. This cut-out C is preferably formed from a single piece of sheet steel, providing a base 20, an inner wall 2| and an outer wall 22. Wall 2i at its base registers with the cover l l as at 24 and continues upward for a short distance, at about the same curvature, after which it curves inwardly more rapidly as indicated, terminating, as at 23, in close proximity to the rotor. 'Ihe outer wall 22 extends from 23, preferably for a short distance in a downward curve as indicated, continuing preferably in a straight line to a point as at 25, I where it may be welded to the base 2l). Screw 5D threaded blocks or nuts 26 may be welded to the base 20, through which registering holes are provided whereby the cut-out C may be detachably held to member I3 by means of bolts 21 as indicated in Figure l.

Applicant does not wish to be limited to the specific shape of cut-out C as shown, because variously designed fans may require differently shaped cut-outs, for example, a cut-out, as shown by dotted lines in Fig. 4 and designated by 22a, may, in some fans, be desirable.

Applicants objects are to provide for any style device of the class, a permanent outlet, large enough whereby the rotor may be removed therethrough, and to provide a detachable cut-out in this outlet which will divide the flow of air with the least possible loss of power.

Applicants cut-out C will permit the air or liquid, as it rushes from between the blades, to be divided at 23, but the air or liquid will not be abruptly checked in this outward and downward movement. As the blades pass the cut-out the air or liquid is divided but permitted to ow outwardly and downwardly on opposite sides of the wedge without sudden distortion or speed change.

It will be understood that the preferred form of the invention has been illustrated and described. Many modications may obviously be made within the scope of the appended claims.

Having thus described my invention what I claim is:

1. A centrifugal device of the class described, comprising a rotor, a housing and an outlet therefor, having a slightly greater depth and width than the diameter and length of said rotor the side in direction of rotation, forming a ledge, a

cut-out positioned on said ledge and adapted to divide and direct the air or liquid into diverging paths, said cut-out having means to be removably attached to said outlet whereby when removed,

said rotor may be removed from said housing 5 through said outlet.

2. A centrifugal fan of the class, comprising a rotor, a housing having an air outlet with a greater length and a greater depth than the length and diameter of said rotor, the side in di- 1o rection of rotor travel forming a ledge, a wedge shaped cut-out positioned on said ledge, having an inner surface which registers with the housing cover, and an outer surface forming a wedge, the apex of which is adapted to split the air current l5 and form outwardly and downwardly extending paths therefor, said cut out being removably attached, whereby when removed said rotor may be removed through said air outlet.

3. A centrifugal device of the class, comprising '20 a housing, a rotor and a cut-out, said housing having an outlet of a size whereby said rotor may be removed therethrough, said cut-out removably attached to one wall of said outlet and occupying part of the depth thereof whereby when removed said rotor may be rem'oved from said housing through said outlet, the inner wall of said cut out registering with the intersecting point between said opening and the cover wall of said housing and continuing for a short distance the contour thereof, the outer wall forming a wedge, the apex of which is adapted to split wedge like, the air or liquid current as 4it leaves said rotor and before reaching the approach side of said outlet.

ERNST WITZEL. 

